Process for the production of nickel salts of monoesters of 3,5-di-tert. butyl-4-hydroxybenzylphosphonic acid

ABSTRACT

Nickel salts of monoesters of 3,5-di-tert.butyl-4hydroxybenzylphosphonic acid are produced by saponifying the corresponding diesters and adding a nickel salt to the reaction mixture. The obtained nickel salts are stabilizers of synthetic polymers.

O United States Patent [151 3,696,135 Kartschmaroff et al. 1 Oct. 3, I972 541 PROCESS FOR THE PRODUCTION OF [56] References Cited NICKEL SALTS OF MONOESTERS OF UNITED STATES PATENTS 3,5-DI-TERT. BUTYL-4- HYDROXYBENZYLPHOSPHONIC ACID 3,310,575 3/ 1967 Splvack ..260/429 R [72] I t P t K rt h ff Arle he m/ 3,395,112 7/1968 Kauder ..260/439RX men 01's: e a mam s 3,488,368 1 1970 S k 39 R X Basel-Land;Paul Moser, Basel, both pwac 260/4 of Switzerland OTHER PUBLICATIONS I Assignw Ciba-Geigy Corporation, Ardsley, Rabinowitz J. Am. Chem. Soc. 82(1960) p. 4564- 7 [22] Filed: July 16, 1970 Primary Examiner-Tobias E. LevOw Assistant Examiner-A. P. Demers [21] Appl. NO.. 55,616 Att0rneyKarl F. JOrda and Martin J. Spellman [30] Foreign Application Priority Data [57] ABSTRACT y 31, 1964 Switzerland -11649/69 Nickel salts of monoesters Of 3,5-di-tert.butyl-4- hydroxybenzylphosphonic acid are produced by U-S. Cl. R, aponifying the corresponding diesters and adding a [51] Int. Cl. ..C07f 15/02 nickel salt to the reaction mixture. The obtained [58] Field of Search ..260/439 nickel salts are stabilizers Of synthetic polymers.

6 Claims, No Drawings PROCESS FOR THE PRODUCTION OF NICKEL SALTS OF MONOESTERS OF 3,5-DI-TERT. BUTYL-4-HYDROXYBENZYLPHOSPI-IONIC ACID DESCRIPTION OF THE INVENTION The invention relates to a process for the production of nickel salts of monoesters of 3,5-di-tert.butyl-4- hydroxybenzylphosphonic acid from corresponding diesters.

Processes are already known for the production of such nickel salts whereby diesters are first saponified in an aqueous medium, the formed monosodium salt or monopotassium salt of the monoester isolated and reacted with nickel salts in a non-aqueous medium. These processes require a series of operations for the separation and drying of the intermediate product, and are therefore time-consuming.

It has now been found that nickel salts of monoesters of 3,5-di-tert.butyl-4-hydroxybenzylphosphonic acid of formula I:

CH: CH: CH:

E3 CH3 wherein R represents the methyl group or ethyl group, are obtained, in a single operation, by saponifying diesters of formula II:

lengthened; In order to reduce this, it is possible to add to the reaction mixture polyvalent alcohols, e.g. ethylene glycol. or monovalent alcohols such as n-butanol, ethylene glycol monomethyl ether, or eythlene glycol monoethyl ether, as a result of which the temperature'of the mixture can be raised, without overpressure, to l00l20C.

A mineral acid, such as hydrochloric acid, is advantageously used for neutralizing or slightly acidifying the reaction mixture after saponification. Suitable as an aqueous nickel salt solution are solutions of nickel chloride, nickel nitrate, nickel sulphate and nickel acetate.

The diesters can be produced in a known manner,

eg by reaction of 3,5-di-tert.butyl-4-hydroxybenzyl neutralizing or slightly acidifying, after saponification,

the reaction mixture; and thereupon adding an aqueous solution of a nickel salt. The nickel salt of the monoester then precipitates almost quantitatively in crystalline form. Surprisingly therefore, the reaction with nickel salts in the aqueous medium which is obtained after saponification and which has a high content of impurities is fully practicable.

Saponification of the diester may be performed with an equivalent amount of caustic solution, i.e. one mole of diester with one mole of sodium hydroxide or potassium hydroxide, when the temperature, at .which saponification is carried out, is sufficiently high. Ad-

vantageously however, an excess of caustic solution is chloride or -'bromide with trimethylor triethylphosphite, as described in the U.S. Pat. No. 3,006,945.

The compounds produced according to the invention are valuable stabilizers, and they serve as agents pro-' tecting against light rays for synthetic polymers, especially for polyolefins; they are also able to improve the dyeing properties of synthetic polymers.

, The temperatures are given in degrees Centigrade in EXAMPLE 1 CH3 CH Hie-0 i 310- CH2- 0 N1 0 H H,c-e 2 5 C 1 (His 2 the following examples.

An amount of 356 g (one mole) of 3,5-di-tert.butyl- 4-hydroxybenzylphosphonic acid diethyl ester are suspended, in a pressure vessel, in a mixture of 160 g of 30 percent sodium hydroxide solution (1.2 moles) and 400 ml of water. The mixture is then heated under nitrogen until an excess pressure of 1.8 to 2.0 atm. is attained, corresponding to a temperature of l25130. This pressure is maintained for 5 hours by heat being supplied. The mixture is afterwards cooled and diluted with 600 ml of water, whereupon the pH-value of the reaction mixture is reduced with ea. 24 g of 30 percent hydrochloric acid to pH 6.0, and the solution cleared by filtration. A solution of 119 g (0.5 moles) of nickel chloride hexahydrate in 60 ml of water is added dropwise in the course of 1 hour to the filtrate, cooled to 3540 and containing the sodium salt of 3,5-ditert.butyl4 -hydroxybenzylphosphonic acid monoethyl ester; and the thereby formed crystalline suspension is subsequently stirred for half an hour at the'same temperature. The mother liquor is then separated by centrifuging, washed with 250 ml of water, and the bluegreen precipitate dried at a pressure of l 1 mm at -8().until the weight remains constant. A yellow powder is obtained, the elemental composition of What we claim is: which corresponds to that of a nickel salt (still contain- 1. Process for the production of nickel salts of ing 2-4 percent water) of the above mentioned semimonoesters f y y ester. The yield is 95 percent of the theoretical value. ybenzylphosphomc acid of formula 1:

CH: CH: Us: /CH:

m4; 0 o 11,0 Ho-Qom-fi-o-m-o-fi-anoQ-on R R H c C \CHS C \CH: (I)

EXAMPLE2 CH3 CH; wherein v I HJC C R represent a methyl group or ethyl group, compris- 9 ing saponifying a diester of the formula 11: HO- onr-i -o N1 CH3 CH CH H 045 \l 3 o 3 CH: 2

342 g (1 mole) of 3,5-ditert.butyl-4-hydroxybenzylphosphonic acid dimethyl ester are suspended,

in a pressure vessel, in a mixture of 400 ml of water and mo TR 224 g of percent potassium hydroxide solution (1,2 moles). This mixture is heated, under nitrogen, to give on, CH3

an excess pressure of 1.8 to 2.0 atm., corresponding to a temperature of l25l30. This pressure is maintained for 5 hours by heat being supplied. The mixture is then cooled, and diluted with 600 ml of water; the

in an aqueous medium, with sodium or potassium 30 hydroxide solution to give the monosodium salt or pl-l-value of the reaction mixture is reduced with ca. 24 monopotflsslufi} Salt 9 the cofrespondlng 9 l g of 30 pe c nt h d hl i id to H 1 and the the reaction mixture 15 neutralized or slightly ac dified solution is then cleared by filtration. Into the filtrate after Sapomficanon; to the F mlxtul'e (cooled to 0 0 containing the potassium Salt of 35 added an aqueous solution ofamckel salt. 3,5-di-tert.butyl-4-hydroxybenzylphosphonic acid f accrdmg to clam wherem the monomethyl ester is added dropwise, in the course of l sapomficanon Performed at a tempergtufe between hour, a l ti f 1 19 g 5 mole) f nickel chloride 1 10 and 140 C, preferably between 125 and 130 C. hexahydrate in 60 ml of water; and the thereby formed PYPCeSS accofdmg to 2, wherein the l'llckel crystalline suspension is afterwards stirred for half an 40 Saltls mcke] chlondehour at the same temperature. The mother liquor is PrPcess {according to claim wherein the nickel now separated by centrifuging; the precipitate is salglspmckel a t l 2 h th k I washed with 250 ml of water, and the blue-green a1 "Pi f g mg 0 Cam erem e me 8 product Subsequently dned a} a l of 11 mm Hg S P igceis c ofd ihg to claim 2, wherein the nickel at 7080 until constant weight 1s attained. A yellow Salt is nickel acetate powder is obtained, the elemental composition of which corresponds to that of a nickel salt (still containing 2-4 percent water) of the above stated semiester.

The yield is 95 percent of the theoretical value. 

2. Process according to claim 1, wherein the saponification is performed at a temperature between 110* and 140* C, preferably between 125* and 130* C.
 3. Process according to claim 2, wherein the nickel salt is nickel chloride.
 4. Process according to claim 2, wherein the nickel salt is nickel nitrate.
 5. Process according to claim 2, wherein the nickel salt is nickel sulphate.
 6. Process according to claim 2, wherein the nickel salt is nickel acetate. 